Internal combustion motor



Jan. 9, 1940. ,K. w. ROHLIN INTERNAL COMBUSTION MOTOR Filed Aug. 30, 1937 4 SheetsSheet 1 INVENTOR Jan. 9, 1940. K. w. ROHLIN INTERNAL COMBUSTION MOTOR 4 Sheets-Sheet 3 Filed Aug. 30. 1937 INVENTOiR Ji'arlhlin u I TOR EY Jan. 9, 1940. K. w. ROHLIN INTERNAL COMBUSTION MOTOR Filed Aug. 50, 1937 4 Sheets-Sheet 4 INVENTOR Patented Jan. 9, 1940 UNITED STATES PATENT OFFICE m'rmmar. COMBUSTION MOTOR Karl w. Rohlin, Dover, Del. 1 4 Application August 30,1937, Serial No. 161,703

14 Claims.

portion may be cut into and out of firing service as power requirements demand.

'The operation of four cylinders of a four-cycle motor imparts a power impulse every 180 movementof the crank shaft, and a six-cylinder, fourcycle motor imparts an impulse every 120. The object of my present invention is to provide means whereby 1 can utilize motors of dissimilar cycles for driving a common crank shaft; the

primary and secondary motors being coordinated to secure eight-cylinder performance and provide power impulses every 90, with the use of only six cylinders.

A particular merit of the fact that it provides for the use of the efficient and reliable four-cycle-type of motor for theprimary or continuous firing portion, while i permitting use of the more powerful two-cycle motor for the secondary or intermittently firing portion. By proper correlation of these two'- 'motor structures, fewer pistons move to cause friction during the whole time the, combination motor operates so that the overall efliciency of the same is'greater than that of conventional motors despite the fact that its two-cycle portion may indicate slightly lower thermal efliciency.

'In order to. coordinate the two portions of the combination motor structure, each having a different thermodynamic cycle, I may make'use of the method and apparatus described in my earlier application, filed December 18, 1936, Serial No. 116,464, and 1 am able to obtain all the benefits of economy, etc., resulting from the use of that invention. The fourcycle cylinders fire whenever the power required of the motor is moderate or low, and the two-cycle cylinders are automatically brought into firing service by mechanism similar to that set forth in myearlier application, whenever high power is required of the motor, or when it rims slowly.

In addition, I have devised another coordinatmy invention resides in ing feature designed to harmonize the power output of each of the two motor portions of different cycles comprising pressure controlling means which. forms an important part of the present invention.

The method and means described in my application above referred to provided for coordinating the operation of two portionsof an internal combustion engine. My present invention provides for coordinating two portions of a motor of different thermodynamic cycles. Y

A feature of my invention is the provision of a combination motor having one portion of a type that may be readily put into operation with conventional starting mechanism, while the remaining portion of the motor may be of a type V that is more or less difficult to put into initial service, such as the two-cycle portion.

A further feature of my invention is the use ofzthe ilexibles, readily controlled, four-cycle portion of the motor during periods when little power is required and the fuel-supply is partially throttled.'

A further feature resulting from of the powerful two-cycle portion of the combination motor structure is the ability to reduce ,motor speed without reducing power output. A

the inclusion.

motor designed in accordance with my present invention can be operated at three-fourths of the speed of a cdnventional motor of the same size and produce as much power. As a result, the mechanical efficiency of the combination motor structure may be appreciably increased and, in addition, many or all of the benefits or' advantages now ascribed to the commercial device known as the "overdrive, are present.

A further feature, resulting from the reduced motor speed and reduced internal friction, and elimination of suction vacuum on all but four of the cylinders during light load conditions, provides much of the benefits attributed to free wheeling.

And a still further feature disclosed by tests of a practical model designed according to the invention of the application above referred to, is'retained in one form of the present structure; namely: heat delivered into .the jacket water is reduced by firing only part of the cylinders most of the time and air passing through the non-firing cylinders serves to cool the motor structure so that the entire cooling load of the a structure is reduced sufficiently to permit, in some cases, elimination of, ;he radiator fan and cooling-water circulating pumps at present required in conventional motors.

In general, this invention may be best carried out by including a group of four-cycle cylinders of twice the number of the two-cycle cylinders;

such arrangement having the merit that eachof minimum vibration result when all of the cylin- Many arrangements of cylinder grouping are within the scope of my invention. In the following description reference is made to acombination motor structure involving the use of six cylinders in line; two of which are of the twocycle type while the rest are of the four-cycle type. Many other arrangements are possible; for instance, the four-cycle cylinders might form one arm of a V while the two-cycle cylinders could form the other arm; such arrangement being equivalent to a conventional eight-cylinder motor. Or, nine cylinders placed in line, six of four-cycle type and three of two-cycle type, would fire like, and be equivalent to, a conventional twelve-cylinder motor. Or, in lieu of this, such nine-cylinder motor could be arranged with six cylinders n one arm of a V and three cylinders on the ot er arm.

These and other features of my invention are more fully set forth hereinafter; reference being had to the accompanying drawings, more or less diagrammatic in character, in which:

Figure 1 is a view in elevation, partly in longitudinal section, of a combination motor structure within the scope of my invention.

Fig. 2 is a cross-sectional view on the line 1I-II, Fig. 1.

Fig. 3 is an enlarged sectional view of one of the carbureters, taken on the line III-III, Fig. 2.

Fig. 4 is a sectional view on the line IV-IV I Fig. 2.

Fig. 5 is an. enlarged sectional view on the line VV, Fig. 1, illustrating blower mechanism em- Fig. 8 is a diagrammatic view of the ignition distributor and its wiring.

Fig. 9 is a graph showing the ratio of pressure drops through the carbureters, and

Fig. 10 is a diagrammatic view showing part of the electrical system of a vehicle such as an automobile, including the interconnected wiring for the control mechanism shown in Fig. 7 and forming part of this invention, as well as that of my companion application, filed August 30,

' 1937; the electrical portion thereof being substantially identical with that shown in Fig. '7 of said companion application, Serial No. 161,702.

As in the structure forming the subject of my co-pending application filed Dec. 18, 1936, Serial No. 116,464, and in that of my companion application, reference is made to manifold channels M and N which feed separate sets of cylinders. In the present instance the manifold channel M communicates with the group of continuouslyfiring cylinders constituting the four-cycle portion of the combination motor, while the manifold channel N communicates with the cylinders of the two-cycle portion of the motor, which fire intermittently.-

The combination motor illustrated in Fig. 1 comprises four cylinders of the four-cycle type, indicated at;I, 2, 3 and 4, and constituting the continuously firing portion of the motor, and two cylinders, indicated at 5 and 6, which constitute the two-cycle portion thereof; the latter being mounted forward of the four-cycle cylinders. The connecting rods for the pistons of the several cylinders are indicated at I, 2, 3 et seq., and

are joined with a crank shaft 1 in the usual manner. The cylinders may be formed in a unitary block, and the crank shaft and the connecting rods for the several pistons are housed by an oil pan indicated at 8. A conventional flywheel is indicated at-9. The usual exhaust manifolds. piping, etc., common to engines of the four-cycle and two-cycle type, are not shown. Other auxiliaries, such as the generator, fuel pump, oil pump, fan and water pumps (if used) are omitted from the drawings for the purpose of simplification.

The crank shaft which I employ with my combination motor will differ from an ordinary crank shaft for a six-cylinder motor wherein explosions take place every 120 of its movement. present instance the crank shaft may be of any usual cast-iron type, similar to that used in a Ford V-8 motor, and may consist of disk-like portion I joining crank throws I 2 3 4, 5 and 6?. In Fig. 1, crank throw I is shown in the extreme rearward position; crank throws 2" and 3* in their extreme forward positions; crank throw 4 in the extreme rearward position; crank throw 5 in the lowest position, and crank throw 6' in the highest position. Crank throws 5e and 6 are disposed at right angles to crank throws I 2, 3 and 4 and the latter are arranged in the usual manner for four-cylinder, four-cycle engine's.

Operation of the separate portions of the combination motor structure is controlled by a series of suction and exhaust valves; those for the fourcycle cylinders being actuated by cams of usual type carried by a cam shaft I0, and indicated at III, while the suction valves of the two-cycle cylinder are actuated by double cams I0 also carried by said cam shaft. The cam shaft is driven at one-half the speed of the crank shaft by timing gears I and I0 mounted on the ends of the crank shaft and cam shaft, respectively.

Intake valves for the cylinders I, 2, 3 and 4, are indicated at I 2 3, and 4, and exhaust valves for said cylinders are indicated at I, 2 3*, and 4*. The intake valves for the cylinders of the two-cycle portion of the motor are indicated at 5 and 6 Such cylinders, as is well known, exhaust through ports in the side walls of the cylinders, one of which is shown in the sectional view, Fig. 2, and indicated at 5*. The several cylinders are fired in turn by a conventional ignition system, including a distributor such as illustrated in Fig. 8, which may be mounted on the front end of the cam shaft.

Independent carbureting means, preferably housed in common or adjacent casings, and indicated at I I and I2, communicate with the manifold channelsM and N, respectively, which deliver to the four-cycle and the two-cycle portions of the motor, respectively. The carbureters may be fitted with air cleaning devices, idling jets, and other features commonly employed.

puts the entire structure in operation. If at In the v passing from float chamber H The fuel in chamberv l I enters at I I from a suitable source past afloat-controlled valve 1 l The pressure choke chamber I! isof the air and vapor in equalized with that in float chamber through pipe il with the result that the flow of air and fuel through Venturi tube ll are both proportional to the drop in pressure between choke chamber l I and the Venturi tube.

Passage of the fuel-air mixture to the manifold channels M and N is controlled by throttle valves [3 and I, mounted on shaft l5, journaled in the manifold walls below the Venturi tubes; the open-- ing of these throttle valves being controlled by the accelerator pedal and by the control about to described. Such fuel-air mixture for the fourcycle portion of the motor then passes through manifold channel M to suction valves i 2 3" and I as said valves are operated in turn .by the cams I 1 The cylinders of the two-cycle portion of the motor receive fuel and air under control of the intake valves and 6 which are operated in turn by the dual cam lifts mounted on the cam shaft III; the respective pistons uncovering the exhaust ports in' the walls of their cylinders (one of which is shown at 5 in. the sectional view, Fig. 2) to relieve and exhaust previously burned gases. For the purpose of delivering air to the cylinders of the two-cycle portion of the motor, I may provide a blower of the 'Root type, having bladed impellers indicated at I6 and I1, arranged in a suitable housing [8; impeller l6 having two blades and being mounted on the end of the crank shaft 1, while impeller I! has four blades and is mounted on the end of the cam shaft Ill. The impellers fit each other and the housing in such manner as to avoid friction and without leaking any appreciable amount of air; thereby eliminating power loss. The impellers move in the direction of the arrows, and displace air under moderate pressure from the intake I8 to the outlet [8 and, if desired, the intake may be fitted with suitable air cleaning and silencing devices. As the speed of the motor increases, the speed of the impellers also increases and efiects delivery of more air for use in cylinders 5 and 6; automatically proportioning to some extent the amount of air delivered to the amountrequired in said cylinders. To insure the delivery of fuel charges of substantially the same volume into the two-cycle cylinders 5 and 6, as 'is delivered into the four-cycle cylinders l, 2, 3 and 4,

- so that the power impulses from all six firing cylinders will be substantially the same in force and smooth motor operation will result, a pressure regulator (hereinafter described) is coordinated with the carbureter l2, and with the cylinders 5 and 6 and their valves and ports. Further regulation of the air delivered to cylinders 5 and 6 is provided by the carbureter valve andnby the pressure regulator.

From outlet la air delivered by the blowers is conducted via tube l8 to butterfly-valve assembly l9, which comprise a pair of butterfly valves w and N mounted on a common shaft l9 journaled in the walls of the passages and oper- 4 atively connected to control mechanism (to be later described) by means of a link l9 From channel l8 .such air passes to channel l9 directly communicating with choke chamber li of carbureter l2, and its pressure is further controlled by regulator 20, comprising a pair of bellows-folded elements 20 and 20 mounted above and to one side of said choke chamber, which elements operate a butterfly escape valve 20, by means of rod 20. The inner space 20 of bellows 20 is in free communication with air channel 20 of the regulator 20.

The annular space 20 between the bellowsfolded; elements 20 and 20 communicates via tube 20 with intake manifold M and the vacuum produced therein by the pumping effect of the pistons of the four-cycle portion of the motor acts t9 draw the head 20 of the bellows assembly inwardly. The blower pressure in air channel 20 tends to move the head 20 of the bellows assemblyoutwardly, and will in fact do so whenever that pressure is excessive; lifting rod 20 to open valve 20 so as to permit someof the air to escape to the atmosphere ,and lower the pressure in air channel 20.

The degree of pressure maintained by the regulator 20'depends upon the vacuum in manifold channel M and on the proportional areas of the two bellows elements. The curves indicated by the graph shown in Fig. 9, represent generally" 10', in which case the pressures indicated at p and p and maintained in air channel 20 and carbureter l2 by the pressure regulator 20 will be one-half as much. above atmospheric pressure as the vacua in manifold channel M and indicated v5 and v are below the atmosphere.

Venturi tube I2 and metering jet l2 are proportioned to deliver the requisite quantity of fuel, and throttle valve l4 mounted on shaft I5 is proportioned to deliver the requisite amount of fuel-air mixture under this scale of pressures;

taking into consideration the pulsating nature of. flow through such carbureter, particularly when it is appliedvto two cylinders of the two cycle type.

It will therefore be seen that pressure regulater 20 'maintains through carbureter l2 and butterfly throttle valve M a scale of pressure drops that are definitely proportional to the pressure drops through carbureter H and butterfly throttle valve l3; the pressures in the first instance being entirely above the atmosphere and in the second instance belowthe atmosphere. When driving conditions cause a large pressure drop through carbureter II in its throttled condition feeding the continuously firing cylinders of the four-cycle portion of the motor, a proportionately, large pressure drop will be created through carbureter I! in its throttled condition feeding the intermittently firing cylinders of the two-cycle portion of the motor, and vice versa. By mounting the throttle valves [3 and M on the same shaft, the same angular opening of both valves is insured, and likewiseproportional areas through them, for allthrottl'e positions. The flow of air and fuel through both carbureters l l and I2 is therefore proportional for all driving conditions during six-cylinder firing so that the delivery of fuel to each group of cylinders is proportional to their requirements and the resulting power impulses are substantially equal and uniform. And the power output of my improved motorclosely approximates that of a conventional eight-cylinder motor of similar bore and stroke. a

The above-described means for equalizing fuel and air delivery to both sets of cylinders enables power compensation mechanism, such as that described in my companion application but not shown in the accompanying drawings, to operate eflectively; such mechanism maintaining the power output substantially constant when the cylinders of the two-cycle motor section are cut into or out of firing service.

In the present instance I have shown in Figs. 1 and '7; the latter view being in detail; a form of control mechanism substantially like that illustrated in rmr co-pending application before referred to but differing from that of my companion application filed of even date herewith in that the piston element of the present control device is actuated pneumatically while the piston element of my companion application is actuated hydraulically. In the present instance a bored block 22 supports a bellows element 22, and a solenoid coil 22 the latter having a movable armature 22 which is raised and lowered to affect the position of a piston element 23 which in turn controls the operation of the combination motor structure. A chamber 23 is disposed below the block 22 within which the piston element 23 is movably mounted and the latter is moved by the vacuum in manifold charmel M communicating via tube 22 with the passages 22 and 22 in the block 22; inlet and exhaust from such passages being controlled by valve portions 22 and 22 carried by the solenoid armature.

Whenever the speed of the battery charging generator is high enough to cause the cut-out to close its switch, and whenever the vacuum in manifold channel M is high enough to aifect the bellows element 22 and close switch 22 provided that at the same time the clutch pedal is up, coil 22 will be energized and will lift the armature 22; the valve portion 22 thereof being moved in to position to connect, passage 22 with tube 22 and the valve portion 22 being moved to position to connect passage 22 with a passage 22 leading to the atmosphere and permit piston 23 to move to the left. If the generator speed falls low enough to open the cut-out, or if the load on the motor increases enough to reduce the vacuum in manifold channel M to the point where switch 22 opens, or if the clutch pedal is depressed, then the circuit to coil 22 will be broken and armature 22 will fall. In such position valve portions 22 and 22 connect passages 22 and 22 in the manner shown in Fig. '7 wherein the piston is at the right of the chamber 23 When control 22 functions to cut the cylinders 'of the two-cycle portion of the motor out of firing service, its piston 23 moves to the left, drawing down lever 22 and effecting, through link I9 rotation of valve shaft I9, counter-clockwise. Butterfly valve I9 is then closed, preventing air flow through carbureter I2, and delivery of fuel thereby. Butterfly valve I9, also mounted on shaft I9, moves from its previously closed position to wide open position so that all of the air delivered by the blower, except that passing valve 20, will be by-passed around carbureter I2 via channel I9 directly into manifold channel N for being out of firing service.

passage .to cylinders 5 and 6 whenever intake valves 5' and 6' are opened; such air simply serving to cool these cylinders during their non-firing p riods.

Rotation of valve-carrying shaft Il operates the compensation mechanism above referred to, part of which is mounted on said shaft, to maintain uniform power output during the change from six to four cylinders in firing service.

When control 22 operates to effect the firing of six cylinders, piston 23 moves to the right, as indicated in Fig. 7, link I 9* is raised, shaft I9 rotates clockwise, butterflyvalve I9- is closed to prevent direct delivery of air through channel [8 to manifold N for passage to cylinders 5 and 8, and butterfly valve I 9 is opened to permit delivery of fuel and air from carburetor I2 to these cylinders under control of throttle valve shaft I5 and pressure regulator 20.

Each of the carbureters II and I2 contain a Venturi tube, indicated at I I" and I2; separate metering jets I I and I2; separate float chambers I I and I2, with separate floats, and separate needle valves II and I2, for controlling the admission of fuel to float chambers II and I2, and separate equalizing pipes II and I2 for equalizing the respective float and choke chambers.

For the purpose of firing the fuel charges in the cylinders at the proper time and in the proper order, I may employ distributing means such as shown in Fig. 8 having a distributor arm 25 which may be mounted on and driven by the cam shaft I; said arm delivering high voltage current to contacts l 2 3 et seq., which are so wired to the spark plugs, indicated at I, 2, 3, et seq., that, in the present instance, the cylinders fire in the following order, viz: I, 8, 2, I, 4, 6, 3, 5. To effect this firing order in a six-cylinder combination motor structure of the type forming the subject of my invention, a distributor for an eight-cylinder, four-cycle, motor may be used, with two of its eight high tension leads connected in pairsto each of the spark plugs and 6. The other four leads will be connected to the spark plugs l, 2, 3, and 4 singly in the conventional manner.

The crankshaft and the distributor mechanism will coordinate to deliver one power impulse for each 90 movement of the crank shaft when all cylinders fire, so that the operation 'of the motor structure of my present invention will substantially equal in smoothness and power output the conventional eight-cylinder, four-cycle motor, in which explosions normally occur every 90". During periods of reduced load, when the controlling mechanism operates to fire four cylinders only, the firing order will be I, 2, 4, 3; cylinders 5 and 6 Explosions and power impulses then occur every 180", just as they do in a conventional four-cylinder, four-cycle motor.

Provided the clutch pedal switch is closed, armature 22 will always be raised when the accelerator pedal is in its highest or idling position. When coil 22 is energized to raise armaswitch: both being similar to that shown in my 7' on the piston shaft, through a lever 22 and a connecting link 22 constitutes the non-flutter means, and actuation of the other end of lever 22 by the armature 22 constitutes the means for avoiding chatter. When piston 23 moves to the left to position the mechanism to fire four cylinders, eccentric 22 moves lever 22, raising link 22 -and the outer end of lever 22 to which itis connected; thereby resetting the point at which switch 22 may be operated by bellows 22' so that piston 23 will not return to its six-cylinder firing position without a considerable change in the vacuum afiecting bellows 22. In this manner an immediate return of the mechanism to' the six-cylinder position, or flutter, is avoided.

Lever 22 is also raised by armature 22 whenever switch 22 has. made suflicient contact to energize coil 22 to lift the armature, this movement making a more positive contact in switch 22 so that coil 22 will'continue to be energized so as to hold armature 22 up and avoid chatter. If contact 22* breaks, even momentarily, permitting armature 22 to fall, lever 22 moves downward and switch 22 is positively opened, thereby preventing chatter in this instance.

Shaft 24 mounted in the choke chambers carries butterfly valves l l and l2 arranged to choke the air flow to the respective carbureters for the purpose of enriching the fuel -air mixture whenever the-temperature of the motor is subnormal. The position of shaft 24 may be adjusted by means of a lever 25 connected by suitable linkage with the instrument board of the automobile.

The air delivered by the blower is transmitted from space l9 of butterfly valve assembly l9 via channels l9 and l2 to space 2|) which is in free communication with choke chamber l2 of carbureter l2.

' The control mechanism illustrated in Fig. 7 is coordinated with the electrical generator I), battery B, and switches I, C and A. by means of the wiring system shown in Fig. 10, which isfully described in my companion application filed-of even date herewith, Serial No. 161,702, and hereinbefore referred to. o I

Operation of the generator G by the engine forming the subject of this invention below some predetermined speed, will not energize magnetic cutout M sufliciently to attract armature M and close switch M so that the electrical circuit through coil 22 will not be energized (except through accelerator pedal switch A, if such switch is closed), armature 22 will remain in its lower position, and piston 23 will be positioned so that six cylinders fire. When, however, -generator G is riven fast enough to generate sufficient voltaggzo energize magnetic cutout M sufllciently to att ct armature M so as to close switch W and complete the circuit through coil 22 (provided clutch switch C is closed), and provided the load on theengine is light enough to operate under a relatively high vacuum in intake manifold M so as to shorten bellows element 22 and close switch 22', armature 22 will then be raised and piston 23 will be moved to the left to position shaft l9 t o flre four cylinders.

If, however, the load on the engine is increased by depressing accelerator pedal A so as to open butterfly valve I3, or by the vehicle encountering a hill, etc., the vacuum in the manifold M will be reduced, bellows 22 will expand, switch 22' 5 will be opened, coil 22 will no longer be energized, armature 22 will fall, piston 23 will'move to the right and six cylinders will fire. Similarly,

when the engine and the generator speed are reduced sufficiently, switch M will be opened, coil 22 will no longer be energized and six cylinderswill flre. Opening switch C will break the circuit through armature 22 and fire six cylinders.

. Closing switch A will energize coil 22 under any conditions of load and speed, and four cylinders only will fire. optional.

As in my companion application, Serial No. 161,702, magnetic cutout M includes coil M designed to prevent flutter, and control 22 includes eccentric 22", lever 22, link 22 and lever 22, designed to prevent flutter; all of which elements are described in detail in the application just referred to.

' It should be understood that the method and means described in' my companion application filed of even date herewith may also be used in lieu of the mechanism above described to cut the two-cycle,portion of the combination motor into and out of firing service. Such mechanism may be operated hydraulically as described in said companion application and would control the position of adjustable push rods normally serving to actuate intake valves 53 and 6 causing these valves to function in the conventional manner during periods when six cylinders fire, and automatically shortening said rods to permit valves 5 and 6 to remain seated when only four cylinders fire. .In this case the air delivered by the blower would be discharged freely to the atmosphere past butterfly valve l9, whose discharge port would have no connection with the manifold passage N. Such air therefore could not serve to cool the non-firing cylinders as it would in the arrangement shown in the drawings herewith and as above described.

It will be understood that various modifications may be made in the foregoing embodiments of my invention without departing from the spirit and 2.' A motor structure of the internal combusr tion type comprising a group of four-cycle cylinders and a .group of two-cycle cylinders, pistons in said cylinders, means for feeding fuel charges to said cylinders, a crank shaft operatively connected to all of said pistons, and means coordinated with the delivery of smaller fuel charges to the four-cycle cylinders for cutting the twocycle cylinders out of firing service.

3. A motor structure of the internal combustion type comprising a group of four-cycle cylinders and a group of two-cyclecylinders, pistons in said cylinders, means for feeding fuel charges to said cylinders, a crank shaft operatively connected to all of said pistons, and means responsive to increased speed and coordinated with the delivery 01 smaller fuel charges to the four-cycle cylinders for cutting the two-cycle cylinders out of service. r

4. A motor structure of the explosion type comprisinga group of four-cycle cylinders and a The use of switches A and C is v group of two-cycle cylinders, pistons in said cylinders, a crank shaft operatively connected to all of said pistons, and means responsive to vacuum on the four-cycle cylinders for cutting the twocycle cylinders into and out of firing service.

5. A combination motor of the explosion type comprising a group of cylinders of the four-cycle type and a group of cylinders of the two-cycle type; the latter being one-half the number of the former, means for delivering charges of fuel and air to said cylinders, pistons within said cylinders, a common crank shaft operatively connected with said pistons, and automatic means for proportioning the flow of explosive mixture to one group of cylinders in a definite ratio to the flow of explosive mixture to the other group of cylinders.

6. A combination motor of the explosion type comprising a group of cylinders of the four-cycle type and a group of cylinders of the two-cycle type; the latter being one-half the number of the former, means for delivering charges of fuel and air to said cylinders, pistons within said cylinders,

a common-crank shaft operatively connected with said pistons, means for cutting the two-cycle portion of the motor into and out of firing service, and automatic means for increasing the flow of explosive mixture to the four-cycle cylinders when the two-cycle cylinders are out of firing service.

7. A combination motor of the explosion type comprising a group of cylinders of the four-cycle type and a group of cylinders of the two-cycle type; the latter being one-half the number of the former, means for delivering charges of fuel and air to said cylinders, pistons within said cylinders, a common crank shaft operatively connected with all of said pistons, and means for regulating the pressure of fuel mixture before delivery to the two-cycle cylinders in a definite ratio to the pressure of fuel mixture delivered to the fourcycle cylinders.

8. A combination motor of the explosion type comprising a group of cylinders of the four-cycle type and a group of cylinders of the two-cycle type; the latter being one-half the number of the former, separate manifolds for the respective groups of cylinders, means for delivering separate charges of fuel and air to said manifolds for delivery to the respective groups of cylinders, pistons within said cylinders, a common crank shaft operatively connected with said pistons, means' for cutting off delivery of fuel and air to the manifold communicating with the two-cycle portion of the motor to put the same out of firing service, and automaticmeans for increasing the flow of explosive mixture to the four-cycle cylinders when the two-cycle cylinders are out of firing service.

9. A combination motor of the explosion type comprising a group of cylinders of the four-cycle type and a group of cylinders of the two-cycle type; the latter being one-half the number of the former, means for delivering charges of fuel and air tdsaid cylinders, pistons within said cylinders, a common crank shaft operatively connected with all of said pistons, inlet and exhaust valves associated with the cylinders of four-cycle type, inlet valves associated'with the cylinders of two-cycle type, a single cam shaft, single cams on said shaft for operating the valves associated with the fourcycle cylinders, and double cams for operating the valves associated with the two-cycle cylinders.

10. A motor structure of the internal combustion type comprising a group of four-cycle cylinders and a group of two-cycle cylinders under common control, means for delivering fuel charges to said cylinders, pistons in said cylinders, crank shaft connection for said pistons, and means coordinated with the delivery of smaller fuel charges to the four-cycle cylinders for cutting the two-cycle cylinders out of firing service.

11. A motor structure of the internal combustion type comprising a group of four-cycle cylinders and a group of two-cycle cylinders, pistons in said cylinders, carbureting means, an intake manifold for delivering fuel and air to said fourcycle cylinders, crankshaft connection for said pistons, and means responsive to the vacuum in said intake manifold for interrupting fuel delivery to said two-cycle cylinders.

12. A motor structure of the internal combustion type comprising a group of four-cycle cylin ders and a group of two-cycle cylinders under common control, means for delivering fuel charges to said cylinders, pistons in said cylinders, crank shaft connection for said pistons, and

- means affected by the movement of said control for cutting the two-cycle cylinders out of firing service.

13. A motor structure of the internal combustion type comprising a group of four-cycle cylinders and a group of two-cycle cylinders under common control, means for delivering fuel charges to said cylinders, pistons in said cylinders, crank shaft connection for said pistons, and means responsive to crank shaft speed for cutting the two-cycle cylinders out of firing service.

14. A motor structure of the. internal combustion type comprising a group of four-cycle cylinders and a. group of two-cycle cylinders, pistons in said cylinders, carbureting means, an intake manifold for delivering fuel and air to said fourcycle cylinders, crankshaft conneection for said pistons, and means responsive to the load on said four-cycle cylinders for interrupting fuel delivery to said two-cycle cylinders.

' KARL W. ROI-ILIN. 

